MySQL-配置缓冲区池

前言：

在使用完MySQL服务器以后，不能使用光标直接关闭show  即输入exit

还有使用VI编辑器时：

                                    末尾使用:wq代表保存改写内容并退出   

                                                  :q   代表未修改内容只是查看并退出

                                                  :q！代表修改内容后发现更改有误 不保存更改内容且退出

[root@localhost ~]# mysql -uroot -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or g.
Your MySQL connection id is 9
Server version: 8.0.18-commercial MySQL Enterprise Server - Commercial

Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.

mysql> SHOW VARIABLES LIKE 'innodb_buffer_pool_size';
+-------------------------+-----------+
| Variable_name           | Value     |
+-------------------------+-----------+
| innodb_buffer_pool_size | 134217728 |
+-------------------------+-----------+
1 row in set (0.03 sec)

mysql> SET GLOBAL innodb_buffer_size=2700 * 1024 * 1024;
ERROR 1193 (HY000): Unknown system variable 'innodb_buffer_size'
mysql> SET GLOBAL innodb_buffer_pool_size=2700 * 1024 * 1024;
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> SHOW VARIABLES LIKE 'innodb_buffer_pool_size';
+-------------------------+------------+
| Variable_name           | Value      |
+-------------------------+------------+
| innodb_buffer_pool_size | 2952790016 |
+-------------------------+------------+
1 row in set (0.00 sec)

mysql> SHOW VARIABLES LIKE 'innodb_buffer_pool_instances';
+------------------------------+-------+
| Variable_name                | Value |
+------------------------------+-------+
| innodb_buffer_pool_instances | 1     |
+------------------------------+-------+
1 row in set (0.00 sec)


mysql> SHOW VARIABLES LIKE 'innodb_buffer_pool_size';
ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect...
Connection id:    8
Current database: *** NONE ***

+-------------------------+------------+
| Variable_name           | Value      |
+-------------------------+------------+
| innodb_buffer_pool_size | 2147483648 |
+-------------------------+------------+
1 row in set (0.01 sec)

mysql> SHOW VARIABLES LIKE 'innodb_buffer_pool_instances';
+------------------------------+-------+
| Variable_name                | Value |
+------------------------------+-------+
| innodb_buffer_pool_instances | 2     |
+------------------------------+-------+
1 row in set (0.01 sec)

mysql> exit
Bye
[root@localhost ~]# 

新建一个show：

[root@localhost ~]# free
              total        used        free      shared  buff/cache   available
Mem:        3765132     1134952     1953436       50428      676744     2348828
Swap:       4063228           0     4063228
[root@localhost ~]# vi /etc/my.cnf
[root@localhost ~]# systemctl restart mysqld
[root@localhost ~]#